1. Field of the Invention
The present invention relates to a press working apparatus for processing a heated workpiece.
2. Related Art
Conventionally, a press working method in which a heated workpiece is press-worked and then subjected to a quenching process is known. Since a processed product obtained by such a working method has a high strength owing to the quenching process, it is difficult to perform a punching process or a cutting process by a working tool. The punching process or the cutting process of the processed product can be performed by a laser processing. However, in this case, there is a problem that a manufacturing cost is raised, as compared to a case of utilizing the working tool.
JP-A-2005-138111 discloses a working method in which a heated workpiece is press-worked by a pad (punch) and at the same time is punched by a working tool (movable mold) passing through the pad, and then a quenching process is completed. According to this working method, the workpiece can be subjected to a punching process before it has a high strength by the quenching process. Accordingly, it is possible to easily perform the punching process for the workpiece.
However, according to the working method of JP-A-2005-138111, the heated workpiece is press-worked and therefore the pad is thermally expanded due to a heat of the workpiece during the press working. In the meantime, the working tool is caused to perform the punching process for the workpiece and thus just temporarily contacts the workpiece. Accordingly, the amount of thermal expansion of the working tool is small, as compared to the pad. For this reason, a positional relationship between a through hole provided in the pad and the working tool is deviated and thus there is a possibility that the working tool and the pad are interfered with each other. Consequently, there is a risk that a cutting blade of the working tool is worn and thus the processing precision is degraded or the press working cannot be performed due to the damage of the pad.